A reactive ion etching (RIE) process comprising a chlorine source gas and an oxygen source gas with an atomic ratio of chlorine to oxygen in the plasma of at least 6 to 1 is used to etch chromium alloy films such as SiCr, SiCrC, SiCrO, SiCrCO, SiCrCN, SiCrON, SiCrCON, CrO, CrN, CrON, and NiCr for example. Additionally, a fluorine source may be added to the etch chemistry.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for fabricating an integrated circuit comprising the steps of: forming a thin film comprising a silicon-chromium alloy on a dielectric layer located on a substrate of said integrated circuit; providing a photoresist pattern on said thin film; and exposing said thin film with said photoresist pattern to a reactive ion etching chemistry comprising a chlorine source, an oxygen source, and a fluorine source wherein an atomic ratio of said chlorine to oxygen is at least 6 to form a thin film resistor within said integrated circuit.
2. The method of claim 1 wherein said silicon-chromium alloy is selected from the group consisting of SiCr, SiCrO, SiCrN, SiCrON, SiCrC, SiCrCO, SiCrCN, and SiCrCON.
3. The method of claim 1 wherein said thin film is SiCrC.
4. The method of claim 1 wherein said exposing step utilizes a source power in a range of 500 to 2000 watts, a pressure in a range of 5 to 200 millitorr, a temperature in a range of 30 to 90 degrees Celsius, an oxygen flow of said oxygen source in a range of 1 to 35 sccm, a chlorine flow of said chlorine source in a range of 6 to 250 sccm, and a CF 4 flow of the fluorine source in a range of 0 to 100 sccm.
5. The method of claim 4 wherein said source power is 1400 watts, said pressure is 8 millitorr, said temperature is 65 degrees Celsius, said oxygen flow is 12 sccm, said chlorine flow is 80 sccm and said CF 4 flow is 10 sccm.
6. A method for fabricating an integrated circuit comprising the steps of: forming a layer of SiCrC on a dielectric layer located on a substrate of said integrated circuit; providing a photoresist pattern on said layer of SiCrC; and exposing said layer of SiCrC with said photoresist pattern to a reactive ion etching chemistry comprising Cl 2 , O 2 , and CF 4 wherein an atomic ratio of chlorine to oxygen is at least 6 to form a thin film resistor within said integrated circuit.
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October 12, 2009
January 19, 2016
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